/*
 * Copyright (c) Huoty, All rights reserved
 * Author: Huoty <sudohuoty@163.com>
 * CreateTime: 2025-06-10 17:02:14
 *
 */

#include <iostream>
#include <string>

using namespace std;

string to_upper(string str) {
    for (auto & c : str) c = toupper(c);
    return str;
}

int main() {
    string s = "hello world";
    cout << to_upper(s) << endl;
}
